Effect of dexmedetomidine on ERK/Na +-K +-ATPase signaling pathway in lung tissues of rats with mechanical ventilation-induced lung injury / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the effect of dexmedetomidine on the extracellular signal-regulated kinase(ERK)/sodium-potassium ATPase(Na + -K + -ATPase)signaing pathway in lung tissues of rats with mechanical ventilation-induced lung injury (VILI). Methods:Forty-eighty clean-grade male Sprague-Dawley rats, weighing 270-320 g, aged 4-5 months, were divided into 4 groups ( n=12 each) using a random number table method: control group (group C), VILI (alpha2-adrenergic receptor antagonist) group (group V), dexmedetomidine group (group D), and dexmedetomidine plus yohimbine group (group DY). Group C underwent no mechanical ventilation and breathed air spontaneously for 4 h. Mechanical ventilation (respiratory rate 40 breaths/min, tidal volume 40 ml/kg, inspiratory/expiratory ratio 1∶1, PEEP 0, fraction of inspired oxygen 21%) lasted 4 h in group V. Dexmedetomidine was infused intravenously in a dose of 5.0 μg/kg at 20 min before ventilation followed by an infusion of 5.0 μg·kg -1· h -1 throughout ventilation in group D. In group DY, yohimbine 0.1 mg/kg was injected intravenously at 10 min before dexmedetomidine, and the other treatments were similar to these previously described in group D. Blood samples and lung tissues were taken at 4 h of mechanical ventilation to determine the wet/dry weight ratio (W/D ratio), lung permeability index (LPI), alveolar fluid clearance rate (AFC), and expression of extracellular signal-regulated kinase (ERK), phosphorylated extracellular signal-regulated kinase (p-ERK), and Na + -K + -ATPase in lung tissues (by Western blot) and to observe pathological changes of lung tissues. Results:Compared with group C, LPI and W/D ratio were significantly increased, AFC was decreased, p-ERK expression was up-regulated, and Na + -K + -ATPase expression was down-regulated in group V and group DY ( P<0.05), and no significant change was found in the incidence of the parameters mentioned above in group D ( P>0.05). Compared with group V, LPI and W/D ratio were significantly decreased, AFC was increased, p-ERK expression was down-regulated, Na + -K + -ATPase expression was up-regulated ( P<0.05), and the pathological changes of lung tissues were significantly attenuated in group D, and no significant change was found in the incidence of the parameters mentioned above in group DY ( P>0.05). Compared with group D, LPI and W/D ratio were significantly increased, AFC was decreased, p-ERK expression was up-regulated, Na + -K + -ATPase expression was down-regulated ( P<0.05), and the pathological changes of lung tissues were accentuated in group DY. Conclusion:The mechanism by which dexmedetomidine alleviates VILI may be related to activating alpha2-adrenergic receptors and inhibiting ERK/Na + -K + -ATPase signaling pathway in rats.